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The deposition of organic phase-change materials (PCMs) on the supporting fibers was shown as a simple and effective way to prepare stable composites with thermoregulating properties, which are feasible as functional additives to dry building mixes. However, the preparation of the composite fibers with optimal morphology to improve their content and thermoregulating performance in the target material still remains challenging. Herein, we report on the stable composite fibers prepared by the deposition of organic PCM eicosane on the biopolymeric fibers of fungal mycelium. The prepared composite had a fibrous morphology with the longitudinal diameter of 1–1.5 μm and the latent heat capacity of 63.2 J/g. The composite was mixed with the dry powder of gypsum plaster with the mass content of 15% and 30%. The electron microscopy revealed a homogeneous distribution of the fibers within the hardened plaster layer. The differential scanning calorimetry confirmed that the addition of the composite to the plaster enhances its thermal performance and brings latent heat storage and release capability with latent heat capacity of 8.2 J/g and 18.2 J/g depending on the composite content. The measurement of the temperature in the volume of the hardened plaster demonstrated that the addition of the thermoregulating fibers effectively reduce the heating rate in the range of 37–39°C and the cooling rate in the range of 38–34°C, corresponding to melting and crystallization of eicosane in the composite structure. [ABSTRACT FROM AUTHOR]

The possibility of using composite fibers with phase change properties as a thermoregulating additive to dry building mixes (mortar mix) with the possibility of accumulating thermal energy under the action of sunlight and a high-frequency alternating magnetic field is studied. Composite fibers were obtained by adsorption of the organic phase-change material eicosane on fibers of microfibrillar cellulose modified with magnetite nanoparticles. The obtained composites demonstrated specific values of stored thermal energy in the range of 129-148 J/g, depending on the content of eicosane in their composition. It is shown that the addition of 10–15% wt. of composite fibers to the dry building mix makes it possible to store and release thermal energy in hardened samples in a temperature range of 27-43°C, corresponding to melting and crystallization of the eicosane in the structure of the composite fibers. It was shown that addition of the composites affects the dynamics of heating under the action of artificial sunlight and subsequent cooling: the samples with added fiber showed more intense heating and slower cooling compared with control samples when the temperature reached 35°C. Samples of the hardened mixture with addition of the composite fibers also exhibited the ability to accumulate thermal energy when exposed to a high-frequency alternating magnetic field with its subsequent sustained removal. [ABSTRACT FROM AUTHOR]

Biopolymeric materials appear as promising eco-friendly and biodegradable matrices for the preparation of composite materials. In this work, G. lucidum, T. hirsuta, P. eryngii, F. velutipes, G. applanatum, L. edodes, and H. erinaceus fungi strains were studied and the fastest-growing fungi strains were revealed. The growth rate and the morphology of formed mycelium were studied depending on the fungi strain type and employed feeding substrate (malt agar, cellulose microcrystals, cellulose microfibrills). It was shown that the mycelium of G. lucidum and T. Hirsuta grown on cellulose microfibrils appears as intertwined hyphae with narrow diameter size distribution and has an optimal morphology as a substrate for the preparation of fibrous composite materials.. [ABSTRACT FROM AUTHOR]

In this work, we synthesized samples of carboxylated nanofibrillar cellulose (NFC) and a derivative that is a product of chemical crosslinking of carboxylated NFC with ethylenediamine. The results of transmission electron microscopy revealed that crosslinking does not lead to noticeable morphological changes in the NFC structure. The chemical modification of the carboxylated NFC was confirmed by FTIR spectroscopy. It was found that chemical crosslinking of carboxylated NFC with ethylenediamine leads to an increase in the colloidal stability of aqueous suspensions, water retention capacity, and dynamic viscosity of gels. The study of the rheological characteristics showed that the aqueous dispersions of the obtained samples are pseudoplastic liquids and have thixotropic properties. [ABSTRACT FROM AUTHOR]